Endocrine Abstracts

Introduction: Klinefelter syndrome (KS) is the most common congenital abnormality causing primary hypogonadism. It occurs in about 1 in 660 live male births. The clinical manifestations include tall stature, small testes, gynecomastia and neurocognitive impairment. Nevertheless, the KS phenotype varies greatly, which might be one of the reasons why the syndrome is highly underdiagnosed. KS is associated with several clinical conditions and increased morbidity/mortality. Testosterone replacement therapy helps to prevent or eventually treat some of these abnormalities. Our aim was to study a population of adult patients with KS, by evaluating clinical and anthropometric parameters, as well as their diagnostic features, treatment options and related comorbidities.

Methods: Retrospective study including patients older than 18-years old diagnosed with KS currently followed at the Endocrinology Department at Hospital de Braga.

Results and Discussion: We identified 17 subjects with KS. The average age at diagnosis was 28.6 years (minimum 3 years and maximum 66 years). In general, in children (n=3) the diagnosis was established because of cognitive/linguistic impairments, whereas in adolescence (n=3) the main referral reason was gynecomastia or delayed puberty. Eleven patients were diagnosed at adult age: gynecomastia was also a relevant feature between these subjects (n=3); of the remaining, 2 cases were diagnosed during infertility screening, 1 because of sexual dysfunction symptoms and 1 at the Obesity Clinic. Only 2 subjects presented with genotypic variants (47,XXY/48,XXXY and 48,XXYY); the others presented the classic karyotype (47,XXY). Three of them are currently under psychiatric guidance due to behavior, impulsivity and anxiety problems. We documented 1 case of mediastinal germ cell tumor; no history of breast cancer was reported. Regarding other related comorbidities, the prevalence of type 2 diabetes and hypertension was similar (23.5%); whereas the prevalence of dyslipidemia was higher (35.3%). Obesity, obstructive sleep apnea syndrome and peripheral vascular/coronary disease were also described in our sample. On physical examination, 76.5% presented small testes and 64.7% had gynecomastia. The average stature was 178.0 cm, a wingspan of 182.5 cm and BMI of 25.9 kg/m². Blood biochemistry revealed the following mean results: FSH 34.5 mUI/ml, LH 16.3 mUI/ml and total testosterone 293.37 ng/dl. Five patients performed spermogram, all with azoospermia. Bone densitometry showed osteopenia in 7 cases and lumbar spine osteoporosis in four patients. Testosterone replacement therapy was initiated in 12 subjects (70.6%). Only 1 of them presented a documented side effect (high hematocrit). This descriptive analysis reflects several of the classic features reported in the literature in patients with KS.